1. Field of the Invention
The present invention relates to fluoro substituted 4'-demethylepipodophyllotoxin glucosides, to their use as antitumor agents, and to pharmaceutical compositions containing them.
2. Background Art
4'-Demethylepipodophyllotoxin glucosides of formula I are antitumor agents derived from the naturally occurring lignan, podophyllotoxin II. The method for their ##STR1## synthesis is described in U.S. Pat. No. 3,524,844 to Keller-Juslen et al. Among compounds of formula I, etoposide (Ia) and teniposide (Ib) have been established as clinically useful against a variety of tumors including small cell lung, ovarian, testicular, breast, bladder, brain, non-lymphocytic leukemia, and Hodgkin's disease.
U.S. Pat. Nos. 4,547,567 and 4,716,221 disclose compounds of formula III ##STR2## wherein one of X.sup.1 and X.sup.2 is OH, and the other is an amino, a monoalkylamino, or a dialkylamino group. These derivatives are said to exhibit high water solubility and they represent examples of epipodophyllotoxin glucosides in which the substituents on the sugar portion are modified.